# vfs.py - Mercurial 'vfs' classes
#
# Copyright Olivia Mackall <olivia@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import contextlib
import os
import shutil
import stat
import threading
from typing import (
Optional,
)
from .i18n import _
from .pycompat import (
delattr,
getattr,
setattr,
)
from . import (
encoding,
error,
pathutil,
pycompat,
util,
)
def _avoidambig(path: bytes, oldstat):
"""Avoid file stat ambiguity forcibly
This function causes copying ``path`` file, if it is owned by
another (see issue5418 and issue5584 for detail).
"""
def checkandavoid():
newstat = util.filestat.frompath(path)
# return whether file stat ambiguity is (already) avoided
return not newstat.isambig(oldstat) or newstat.avoidambig(path, oldstat)
if not checkandavoid():
# simply copy to change owner of path to get privilege to
# advance mtime (see issue5418)
util.rename(util.mktempcopy(path), path)
checkandavoid()
class abstractvfs:
"""Abstract base class; cannot be instantiated"""
# default directory separator for vfs
#
# Other vfs code always use `/` and this works fine because python file API
# abstract the use of `/` and make it work transparently. For consistency
# vfs will always use `/` when joining. This avoid some confusion in
# encoded vfs (see issue6546)
_dir_sep = b'/'
def __init__(self, *args, **kwargs):
'''Prevent instantiation; don't call this from subclasses.'''
raise NotImplementedError('attempted instantiating ' + str(type(self)))
# TODO: type return, which is util.posixfile wrapped by a proxy
def __call__(self, path: bytes, mode: bytes = b'rb', **kwargs):
raise NotImplementedError
def _auditpath(self, path: bytes, mode: bytes):
raise NotImplementedError
def join(self, path: Optional[bytes], *insidef: bytes) -> bytes:
raise NotImplementedError
def tryread(self, path: bytes) -> bytes:
'''gracefully return an empty string for missing files'''
try:
return self.read(path)
except FileNotFoundError:
pass
return b""
def tryreadlines(self, path: bytes, mode: bytes = b'rb'):
'''gracefully return an empty array for missing files'''
try:
return self.readlines(path, mode=mode)
except FileNotFoundError:
pass
return []
@util.propertycache
def open(self):
"""Open ``path`` file, which is relative to vfs root.
Newly created directories are marked as "not to be indexed by
the content indexing service", if ``notindexed`` is specified
for "write" mode access.
"""
return self.__call__
def read(self, path: bytes) -> bytes:
with self(path, b'rb') as fp:
return fp.read()
def readlines(self, path: bytes, mode: bytes = b'rb'):
with self(path, mode=mode) as fp:
return fp.readlines()
def write(
self, path: bytes, data: bytes, backgroundclose=False, **kwargs
) -> int:
with self(path, b'wb', backgroundclose=backgroundclose, **kwargs) as fp:
return fp.write(data)
def writelines(
self, path: bytes, data: bytes, mode: bytes = b'wb', notindexed=False
) -> None:
with self(path, mode=mode, notindexed=notindexed) as fp:
return fp.writelines(data)
def append(self, path: bytes, data: bytes) -> int:
with self(path, b'ab') as fp:
return fp.write(data)
def basename(self, path: bytes) -> bytes:
"""return base element of a path (as os.path.basename would do)
This exists to allow handling of strange encoding if needed."""
return os.path.basename(path)
def chmod(self, path: bytes, mode: int) -> None:
return os.chmod(self.join(path), mode)
def dirname(self, path: bytes) -> bytes:
"""return dirname element of a path (as os.path.dirname would do)
This exists to allow handling of strange encoding if needed."""
return os.path.dirname(path)
def exists(self, path: Optional[bytes] = None) -> bool:
return os.path.exists(self.join(path))
def fstat(self, fp):
return util.fstat(fp)
def isdir(self, path: Optional[bytes] = None) -> bool:
return os.path.isdir(self.join(path))
def isfile(self, path: Optional[bytes] = None) -> bool:
return os.path.isfile(self.join(path))
def islink(self, path: Optional[bytes] = None) -> bool:
return os.path.islink(self.join(path))
def isfileorlink(self, path: Optional[bytes] = None) -> bool:
"""return whether path is a regular file or a symlink
Unlike isfile, this doesn't follow symlinks."""
try:
st = self.lstat(path)
except OSError:
return False
mode = st.st_mode
return stat.S_ISREG(mode) or stat.S_ISLNK(mode)
def _join(self, *paths: bytes) -> bytes:
root_idx = 0
for idx, p in enumerate(paths):
if os.path.isabs(p) or p.startswith(self._dir_sep):
root_idx = idx
if root_idx != 0:
paths = paths[root_idx:]
paths = [p for p in paths if p]
return self._dir_sep.join(paths)
def reljoin(self, *paths: bytes) -> bytes:
"""join various elements of a path together (as os.path.join would do)
The vfs base is not injected so that path stay relative. This exists
to allow handling of strange encoding if needed."""
return self._join(*paths)
def split(self, path: bytes):
"""split top-most element of a path (as os.path.split would do)
This exists to allow handling of strange encoding if needed."""
return os.path.split(path)
def lexists(self, path: Optional[bytes] = None) -> bool:
return os.path.lexists(self.join(path))
def lstat(self, path: Optional[bytes] = None):
return os.lstat(self.join(path))
def listdir(self, path: Optional[bytes] = None):
return os.listdir(self.join(path))
def makedir(self, path: Optional[bytes] = None, notindexed=True):
return util.makedir(self.join(path), notindexed)
def makedirs(
self, path: Optional[bytes] = None, mode: Optional[int] = None
):
return util.makedirs(self.join(path), mode)
def makelock(self, info, path: bytes):
return util.makelock(info, self.join(path))
def mkdir(self, path: Optional[bytes] = None):
return os.mkdir(self.join(path))
def mkstemp(
self,
suffix: bytes = b'',
prefix: bytes = b'tmp',
dir: Optional[bytes] = None,
):
fd, name = pycompat.mkstemp(
suffix=suffix, prefix=prefix, dir=self.join(dir)
)
dname, fname = util.split(name)
if dir:
return fd, os.path.join(dir, fname)
else:
return fd, fname
def readdir(self, path: Optional[bytes] = None, stat=None, skip=None):
return util.listdir(self.join(path), stat, skip)
def readlock(self, path: bytes) -> bytes:
return util.readlock(self.join(path))
def rename(self, src: bytes, dst: bytes, checkambig=False):
"""Rename from src to dst
checkambig argument is used with util.filestat, and is useful
only if destination file is guarded by any lock
(e.g. repo.lock or repo.wlock).
To avoid file stat ambiguity forcibly, checkambig=True involves
copying ``src`` file, if it is owned by another. Therefore, use
checkambig=True only in limited cases (see also issue5418 and
issue5584 for detail).
"""
self._auditpath(dst, b'w')
srcpath = self.join(src)
dstpath = self.join(dst)
oldstat = checkambig and util.filestat.frompath(dstpath)
if oldstat and oldstat.stat:
ret = util.rename(srcpath, dstpath)
_avoidambig(dstpath, oldstat)
return ret
return util.rename(srcpath, dstpath)
def readlink(self, path: bytes) -> bytes:
return util.readlink(self.join(path))
def removedirs(self, path: Optional[bytes] = None):
"""Remove a leaf directory and all empty intermediate ones"""
return util.removedirs(self.join(path))
def rmdir(self, path: Optional[bytes] = None):
"""Remove an empty directory."""
return os.rmdir(self.join(path))
def rmtree(
self, path: Optional[bytes] = None, ignore_errors=False, forcibly=False
):
"""Remove a directory tree recursively
If ``forcibly``, this tries to remove READ-ONLY files, too.
"""
if forcibly:
def onexc(function, path, excinfo):
if function is not os.remove:
raise
# read-only files cannot be unlinked under Windows
s = os.stat(path)
if (s.st_mode & stat.S_IWRITE) != 0:
raise
os.chmod(path, stat.S_IMODE(s.st_mode) | stat.S_IWRITE)
os.remove(path)
else:
onexc = None
try:
# pytype: disable=wrong-keyword-args
return shutil.rmtree(
self.join(path), ignore_errors=ignore_errors, onexc=onexc
)
# pytype: enable=wrong-keyword-args
except TypeError: # onexc was introduced in Python 3.12
return shutil.rmtree(
self.join(path), ignore_errors=ignore_errors, onerror=onexc
)
def setflags(self, path: bytes, l: bool, x: bool):
return util.setflags(self.join(path), l, x)
def stat(self, path: Optional[bytes] = None):
return os.stat(self.join(path))
def unlink(self, path: Optional[bytes] = None):
return util.unlink(self.join(path))
def tryunlink(self, path: Optional[bytes] = None):
"""Attempt to remove a file, ignoring missing file errors."""
util.tryunlink(self.join(path))
def unlinkpath(
self, path: Optional[bytes] = None, ignoremissing=False, rmdir=True
):
return util.unlinkpath(
self.join(path), ignoremissing=ignoremissing, rmdir=rmdir
)
def utime(self, path: Optional[bytes] = None, t=None):
return os.utime(self.join(path), t)
def walk(self, path: Optional[bytes] = None, onerror=None):
"""Yield (dirpath, dirs, files) tuple for each directories under path
``dirpath`` is relative one from the root of this vfs. This
uses ``os.sep`` as path separator, even you specify POSIX
style ``path``.
"The root of this vfs" is represented as empty ``dirpath``.
"""
root = os.path.normpath(self.join(None))
# when dirpath == root, dirpath[prefixlen:] becomes empty
# because len(dirpath) < prefixlen.
prefixlen = len(pathutil.normasprefix(root))
for dirpath, dirs, files in os.walk(self.join(path), onerror=onerror):
yield (dirpath[prefixlen:], dirs, files)
@contextlib.contextmanager
def backgroundclosing(self, ui, expectedcount=-1):
"""Allow files to be closed asynchronously.
When this context manager is active, ``backgroundclose`` can be passed
to ``__call__``/``open`` to result in the file possibly being closed
asynchronously, on a background thread.
"""
# Sharing backgroundfilecloser between threads is complex and using
# multiple instances puts us at risk of running out of file descriptors
# only allow to use backgroundfilecloser when in main thread.
if not isinstance(
threading.current_thread(),
threading._MainThread, # pytype: disable=module-attr
):
yield
return
vfs = getattr(self, 'vfs', self)
if getattr(vfs, '_backgroundfilecloser', None):
raise error.Abort(
_(b'can only have 1 active background file closer')
)
with backgroundfilecloser(ui, expectedcount=expectedcount) as bfc:
try:
vfs._backgroundfilecloser = (
bfc # pytype: disable=attribute-error
)
yield bfc
finally:
vfs._backgroundfilecloser = (
None # pytype: disable=attribute-error
)
def register_file(self, path):
"""generic hook point to lets fncache steer its stew"""
class vfs(abstractvfs):
"""Operate files relative to a base directory
This class is used to hide the details of COW semantics and
remote file access from higher level code.
'cacheaudited' should be enabled only if (a) vfs object is short-lived, or
(b) the base directory is managed by hg and considered sort-of append-only.
See pathutil.pathauditor() for details.
"""
def __init__(
self,
base: bytes,
audit=True,
cacheaudited=False,
expandpath=False,
realpath=False,
):
if expandpath:
base = util.expandpath(base)
if realpath:
base = os.path.realpath(base)
self.base = base
self._audit = audit
if audit:
self.audit = pathutil.pathauditor(self.base, cached=cacheaudited)
else:
self.audit = lambda path, mode=None: True
self.createmode = None
self._trustnlink = None
self.options = {}
@util.propertycache
def _cansymlink(self) -> bool:
return util.checklink(self.base)
@util.propertycache
def _chmod(self):
return util.checkexec(self.base)
def _fixfilemode(self, name):
if self.createmode is None or not self._chmod:
return
os.chmod(name, self.createmode & 0o666)
def _auditpath(self, path, mode) -> None:
if self._audit:
if os.path.isabs(path) and path.startswith(self.base):
path = os.path.relpath(path, self.base)
r = util.checkosfilename(path)
if r:
raise error.Abort(b"%s: %r" % (r, path))
self.audit(path, mode=mode)
def isfileorlink_checkdir(
self, dircache, path: Optional[bytes] = None
) -> bool:
"""return True if the path is a regular file or a symlink and
the directories along the path are "normal", that is
not symlinks or nested hg repositories.
Ignores the `_audit` setting, and checks the directories regardless.
`dircache` is used to cache the directory checks.
"""
try:
for prefix in pathutil.finddirs_rev_noroot(util.localpath(path)):
if prefix in dircache:
res = dircache[prefix]
else:
res = pathutil.pathauditor._checkfs_exists(
self.base, prefix, path
)
dircache[prefix] = res
if not res:
return False
except (OSError, error.Abort):
return False
return self.isfileorlink(path)
def __call__(
self,
path: bytes,
mode: bytes = b"rb",
atomictemp=False,
notindexed=False,
backgroundclose=False,
checkambig=False,
auditpath=True,
makeparentdirs=True,
):
"""Open ``path`` file, which is relative to vfs root.
By default, parent directories are created as needed. Newly created
directories are marked as "not to be indexed by the content indexing
service", if ``notindexed`` is specified for "write" mode access.
Set ``makeparentdirs=False`` to not create directories implicitly.
If ``backgroundclose`` is passed, the file may be closed asynchronously.
It can only be used if the ``self.backgroundclosing()`` context manager
is active. This should only be specified if the following criteria hold:
1. There is a potential for writing thousands of files. Unless you
are writing thousands of files, the performance benefits of
asynchronously closing files is not realized.
2. Files are opened exactly once for the ``backgroundclosing``
active duration and are therefore free of race conditions between
closing a file on a background thread and reopening it. (If the
file were opened multiple times, there could be unflushed data
because the original file handle hasn't been flushed/closed yet.)
``checkambig`` argument is passed to atomictempfile (valid
only for writing), and is useful only if target file is
guarded by any lock (e.g. repo.lock or repo.wlock).
To avoid file stat ambiguity forcibly, checkambig=True involves
copying ``path`` file opened in "append" mode (e.g. for
truncation), if it is owned by another. Therefore, use
combination of append mode and checkambig=True only in limited
cases (see also issue5418 and issue5584 for detail).
"""
if auditpath:
self._auditpath(path, mode)
f = self.join(path)
if b"b" not in mode:
mode += b"b" # for that other OS
nlink = -1
if mode not in (b'r', b'rb'):
dirname, basename = util.split(f)
# If basename is empty, then the path is malformed because it points
# to a directory. Let the posixfile() call below raise IOError.
if basename:
if atomictemp:
if makeparentdirs:
util.makedirs(dirname, self.createmode, notindexed)
return util.atomictempfile(
f, mode, self.createmode, checkambig=checkambig
)
try:
if b'w' in mode:
util.unlink(f)
nlink = 0
else:
# nlinks() may behave differently for files on Windows
# shares if the file is open.
with util.posixfile(f):
nlink = util.nlinks(f)
if nlink < 1:
nlink = 2 # force mktempcopy (issue1922)
except FileNotFoundError:
nlink = 0
if makeparentdirs:
util.makedirs(dirname, self.createmode, notindexed)
if nlink > 0:
if self._trustnlink is None:
self._trustnlink = nlink > 1 or util.checknlink(f)
if nlink > 1 or not self._trustnlink:
util.rename(util.mktempcopy(f), f)
fp = util.posixfile(f, mode)
if nlink == 0:
self._fixfilemode(f)
if checkambig:
if mode in (b'r', b'rb'):
raise error.Abort(
_(
b'implementation error: mode %s is not'
b' valid for checkambig=True'
)
% mode
)
fp = checkambigatclosing(fp)
if backgroundclose and isinstance(
threading.current_thread(),
threading._MainThread, # pytype: disable=module-attr
):
if (
not self._backgroundfilecloser # pytype: disable=attribute-error
):
raise error.Abort(
_(
b'backgroundclose can only be used when a '
b'backgroundclosing context manager is active'
)
)
fp = delayclosedfile(
fp,
self._backgroundfilecloser, # pytype: disable=attribute-error
)
return fp
def symlink(self, src: bytes, dst: bytes) -> None:
self.audit(dst)
linkname = self.join(dst)
util.tryunlink(linkname)
util.makedirs(os.path.dirname(linkname), self.createmode)
if self._cansymlink:
try:
os.symlink(src, linkname)
except OSError as err:
raise OSError(
err.errno,
_(b'could not symlink to %r: %s')
% (src, encoding.strtolocal(err.strerror)),
linkname,
)
else:
self.write(dst, src)
def join(self, path: Optional[bytes], *insidef: bytes) -> bytes:
if path:
parts = [self.base, path]
parts.extend(insidef)
return self._join(*parts)
else:
return self.base
opener = vfs
class proxyvfs(abstractvfs):
def __init__(self, vfs: "vfs"):
self.vfs = vfs
@property
def createmode(self):
return self.vfs.createmode
def _auditpath(self, path, mode):
return self.vfs._auditpath(path, mode)
@property
def options(self):
return self.vfs.options
@options.setter
def options(self, value):
self.vfs.options = value
class filtervfs(proxyvfs, abstractvfs):
'''Wrapper vfs for filtering filenames with a function.'''
def __init__(self, vfs: "vfs", filter):
proxyvfs.__init__(self, vfs)
self._filter = filter
def __call__(self, path: bytes, *args, **kwargs):
return self.vfs(self._filter(path), *args, **kwargs)
def join(self, path: Optional[bytes], *insidef: bytes) -> bytes:
if path:
return self.vfs.join(self._filter(self.vfs.reljoin(path, *insidef)))
else:
return self.vfs.join(path)
filteropener = filtervfs
class readonlyvfs(proxyvfs):
'''Wrapper vfs preventing any writing.'''
def __init__(self, vfs: "vfs"):
proxyvfs.__init__(self, vfs)
def __call__(self, path: bytes, mode: bytes = b'rb', *args, **kw):
if mode not in (b'r', b'rb'):
raise error.Abort(_(b'this vfs is read only'))
return self.vfs(path, mode, *args, **kw)
def join(self, path: Optional[bytes], *insidef: bytes) -> bytes:
return self.vfs.join(path, *insidef)
class closewrapbase:
"""Base class of wrapper, which hooks closing
Do not instantiate outside of the vfs layer.
"""
def __init__(self, fh):
object.__setattr__(self, '_origfh', fh)
def __getattr__(self, attr):
return getattr(self._origfh, attr)
def __setattr__(self, attr, value):
return setattr(self._origfh, attr, value)
def __delattr__(self, attr):
return delattr(self._origfh, attr)
def __enter__(self):
self._origfh.__enter__()
return self
def __exit__(self, exc_type, exc_value, exc_tb):
raise NotImplementedError('attempted instantiating ' + str(type(self)))
def close(self):
raise NotImplementedError('attempted instantiating ' + str(type(self)))
class delayclosedfile(closewrapbase):
"""Proxy for a file object whose close is delayed.
Do not instantiate outside of the vfs layer.
"""
def __init__(self, fh, closer):
super(delayclosedfile, self).__init__(fh)
object.__setattr__(self, '_closer', closer)
def __exit__(self, exc_type, exc_value, exc_tb):
self._closer.close(self._origfh)
def close(self):
self._closer.close(self._origfh)
class backgroundfilecloser:
"""Coordinates background closing of file handles on multiple threads."""
def __init__(self, ui, expectedcount=-1):
self._running = False
self._entered = False
self._threads = []
self._threadexception = None
# Only Windows/NTFS has slow file closing. So only enable by default
# on that platform. But allow to be enabled elsewhere for testing.
defaultenabled = pycompat.iswindows
enabled = ui.configbool(b'worker', b'backgroundclose', defaultenabled)
if not enabled:
return
# There is overhead to starting and stopping the background threads.
# Don't do background processing unless the file count is large enough
# to justify it.
minfilecount = ui.configint(b'worker', b'backgroundcloseminfilecount')
# FUTURE dynamically start background threads after minfilecount closes.
# (We don't currently have any callers that don't know their file count)
if expectedcount > 0 and expectedcount < minfilecount:
return
maxqueue = ui.configint(b'worker', b'backgroundclosemaxqueue')
threadcount = ui.configint(b'worker', b'backgroundclosethreadcount')
ui.debug(
b'starting %d threads for background file closing\n' % threadcount
)
self._queue = pycompat.queue.Queue(maxsize=maxqueue)
self._running = True
for i in range(threadcount):
t = threading.Thread(target=self._worker, name='backgroundcloser')
self._threads.append(t)
t.start()
def __enter__(self):
self._entered = True
return self
def __exit__(self, exc_type, exc_value, exc_tb):
self._running = False
# Wait for threads to finish closing so open files don't linger for
# longer than lifetime of context manager.
for t in self._threads:
t.join()
def _worker(self):
"""Main routine for worker thread."""
while True:
try:
fh = self._queue.get(block=True, timeout=0.100)
# Need to catch or the thread will terminate and
# we could orphan file descriptors.
try:
fh.close()
except Exception as e:
# Stash so can re-raise from main thread later.
self._threadexception = e
except pycompat.queue.Empty:
if not self._running:
break
def close(self, fh):
"""Schedule a file for closing."""
if not self._entered:
raise error.Abort(
_(b'can only call close() when context manager active')
)
# If a background thread encountered an exception, raise now so we fail
# fast. Otherwise we may potentially go on for minutes until the error
# is acted on.
if self._threadexception:
e = self._threadexception
self._threadexception = None
raise e
# If we're not actively running, close synchronously.
if not self._running:
fh.close()
return
self._queue.put(fh, block=True, timeout=None)
class checkambigatclosing(closewrapbase):
"""Proxy for a file object, to avoid ambiguity of file stat
See also util.filestat for detail about "ambiguity of file stat".
This proxy is useful only if the target file is guarded by any
lock (e.g. repo.lock or repo.wlock)
Do not instantiate outside of the vfs layer.
"""
def __init__(self, fh):
super(checkambigatclosing, self).__init__(fh)
object.__setattr__(self, '_oldstat', util.filestat.frompath(fh.name))
def _checkambig(self):
oldstat = self._oldstat
if oldstat.stat:
_avoidambig(self._origfh.name, oldstat)
def __exit__(self, exc_type, exc_value, exc_tb):
self._origfh.__exit__(exc_type, exc_value, exc_tb)
self._checkambig()
def close(self):
self._origfh.close()
self._checkambig()